An existing backlight system used for a liquid crystal display device mainly comprises a reflective film, a light guide plate and an optical film, none of which, however, conduct individual optical processing on a single pixel unit. That is to say, light emitted from a backlight source will generally be incident entirely on a liquid crystal display panel, i.e., the backlight may be partially incident on a data line or gate line of an array substrate and thus wasted. The shading of the partial backlight by the data line or gate line on the array substrate will give rise to backlight losses and lower its utilization rate.
Generally speaking, in the art, in order to improve the utilization rate of backlight and the light transmittance of a liquid crystal display device, it is often required to increase the aperture ratio of a liquid crystal pixel window. However, such an increase in the aperture ratio tends to cause other multiple problems easily, such as increased processing steps, increased process difficulty and increased manufacturing costs, which are disadvantageous in the actual production.